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1.
From extraction experiments and $ \gamma $ -activity measurements, the extraction constant corresponding to the equilibrium $ {\text{Eu}}^{ 3+ } \left( {\text{aq}} \right) + 3 {\text{A}}^{ - } \left( {\text{aq}} \right) + {\mathbf{1}}\left( {\text{nb}} \right) \Leftrightarrow {\mathbf{1}} \cdot {\text{Eu}}^{ 3+ } \left( {\text{nb}} \right) + 3 {\text{A}}^{ - } \left( {\text{nb}} \right) $ taking place in the two-phase water–nitrobenzene system ( $ {\text{A}}^{ - } = \text {CF}_{3} \text{SO}_{3}^{ - } $ ; 1 = macrocyclic lactam receptor—see Scheme 1; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as $ { \log } K_{{{\text{ex}} }} ({\mathbf{1}} \cdot {\text{Eu}}^{ 3+ } ,{\text{ 3A}}^{ - } )\; = \; - 4. 9 \pm 0. 1 $ . Further, the stability constant of the 1·Eu3+ cationic complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: $ { \log } \beta_{{{\text{nb}} }} ({\mathbf{1}} \cdot {\text{Eu}}^{ 3+ } ) \; = \; 8. 2 \pm 0. 1 $ . Finally, using DFT calculations, the most probable structure of the cationic complex species 1·Eu3+ was derived. In the resulting 1·Eu3+ complex, the “central” cation Eu3+ is bound by five bond interactions to two ethereal oxygen atoms and two carbonyl oxygens, as well as to one carbon atom of the corresponding benzene ring of the parent macrocyclic lactam receptor 1 via cation-π interaction. Scheme 1
Structural formula of 2,20-dichloro-9,10,11,12,13,14-hexahydro-6H,22H-dibenzo[n,q][1,4,10,13]dioxadiaza-meta-xylyl-7,15(8H,16H)-dione (abbrev. 1) 相似文献
2.
Emanuel Makrlík Zdeňka Sedláková Petr Vaňura Pavel Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2263-2266
From extraction experiments and $ \gamma $ -activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+(aq) + 1·Sr2+(nb) $ \Leftrightarrow $ 1·M2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (M2+ = Mg2+, Ca2+, Ba2+, Pb2+, Cu2+, Zn2+, Cd2+, $ {\hbox{UO}}_{2}^{2 + } $ , Mn2+, Co2+, Ni2+; 1 = macrocyclic lactam receptor–see Scheme 1; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1·M2+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: Mg2+ < Co2+ < Cu2+, Mn2+, Ni2+ < Cd2+ < Ca2+ < Ba2+, Zn2+ < Pb2+ < $ {\hbox{UO}}_{2}^{2 + } $ . Scheme 1
Structural formula of 2,18-dichloro-9,10,11,12-tetrahydro-6H, 20H-dibenzo[l,o][1,11,4,8]dioxadiazacyclohexadecine-7,13(8H, 14H)-dione (abbrev. 1) 相似文献
3.
E. Makrlík Z. Spíchal P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2135-2140
Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of bis(diphenylphosphino)methane dioxide (DPPMDO, L) has been investigated. The equilibrium data have been explained assuming that the species $ {\text{HL}}^{ + } $ , $ {\text{HL}}_{2}^{ + } $ , $ {\text{ML}}_{2}^{3 + } $ , $ {\text{ML}}_{3}^{3 + } $ and $ {\text{ML}}_{4}^{3 + } $ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that the stability constants of the corresponding complexes $ {\text{EuL}}_{n}^{3 + } $ and $ {\text{AmL}}_{n}^{3 + } $ , where n = 2, 3 and L is DPPMDO, in water–saturated nitrobenzene are comparable, whereas in this medium the stability of the cationic species $ {\text{AmL}}_{4}^{3 + } $ (L = DPPMDO) is somewhat higher than that of $ {\text{EuL}}_{4}^{3 + } $ with the same ligand L. 相似文献
4.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium $ {\text{M}}^{ + } \left( {\text{aq}} \right) \, + {\mathbf{1}}\cdot{\text{Na}}^{ + } \left( {\text{nb}} \right) \Leftrightarrow {\mathbf{1}}\cdot{\text{M}}^{ + } \left( {\text{nb}} \right) \, + {\text{Na}}^{ + } \left( {\text{aq}} \right) $ taking place in the two-phase water–nitrobenzene system $ \begin{gathered} ({\text{M}}^{ + } = {\text{ Li}}^{ + } ,{\text{ K}}^{ + } ,{\text{ Rb}}^{ + } ,{\text{ Cs}}^{ + } ,{\text{ H}}_{ 3} {\text{O}}^{ + } ,{\text{NH}}_{4}^{ + }, {\text{ Ag}}^{ + } ,{\text{ Tl}}^{ + } ;{\mathbf{1}} \\ = {\text{ nonactin}};{\text{ aq }} = {\text{ aqueous phase}},{\text{ nb }} = {\text{nitrobenzene phase}}) \\ \end{gathered} $ were determined. Moreover, the stability constants of the 1·M+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of $ {\text{Cs}}^{ + } < {\text{ Rb}}^{ + } < {\text{ H}}_{ 3} {\text{O}}^{ + } ,{\text{ Ag}}^{ + } < {\text{ Tl}}^{ + } < {\text{ Li}}^{ + } < {\text{ K}}^{ + } < {\text{NH}}_{4}^{ + } $ . 相似文献
5.
E. Makrlík P. Selucký P. Vaňura B. A. Moyer 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1015-1018
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + CsL+ (nb) ? ML+ (nb) + Cs+ (aq) taking place in the two–phase water–nitrobenzene system (M+ = K+, Rb+, $ {\text{NH}}_{4}^{ + } $ , Ag+, Tl+; L = calix[4]arene-bis(t-octylbenzo-18-crown-6); aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: $ {\text{NH}}_{4}^{ + } $ < K+ < Ag+ < Rb+ < Tl+. 相似文献
6.
Marco Giardiello Mauro Botta Mark P. Lowe 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):435-444
Two DOTA-based proligands bearing a pendant diphenylphosphinamide 4a and 4b were synthesised. Their Eu(III) complexes exhibit sensitised emission when excited at 270 nm via the diphenylphosphinamide chromophore. Hydration states of q = 1.5 were determined from excited state lifetime measurements (Eu.4a $ k_{{{\text{H}}_{ 2} {\text{O}}}} = 2. 1 4 \,{\text{ms}}^{ - 1} ,\;k_{{{\text{D}}_{ 2} {\text{O}}}} = 0. 6 4 \,{\text{ms}}^{ - 1} $ ; Eu.4b $ k_{{{\text{H}}_{ 2} {\text{O}}}} = 2. 6 7\, {\text{ms}}^{ - 1} ,\;k_{{{\text{D}}_{ 2} {\text{O}}}} = 1. 1 8 \,{\text{ms}}^{ - 1} $ ). In the presence of human serum albumin (HSA) (0.1 mM Eu.4a/b, 0.67 mM HSA, pH 7.4) q = 0.4 for Eu.4a ( $ k_{{{\text{H}}_{ 2} {\text{O}}}} = 1. 3 4\, {\text{ms}}^{ - 1} ,\;k_{{{\text{D}}_{ 2} {\text{O}}}} = 0. 7 5\, {\text{ms}}^{ - 1} $ ) and q = 0.6 for Eu.4b ( $ k_{{{\text{H}}_{ 2} {\text{O}}}} = 1. 8 3\, {\text{ms}}^{ - 1} ,\;k_{{{\text{D}}_{ 2} {\text{O}}}} = 1.0 5 \,{\text{ms}}^{ - 1} $ ). Relaxivites (pH 7.4, 298 K, 20 MHz) of the Gd(III) complexes in the absence and presence of HSA (0.1 mM Gd.4a/b, 0.67 mM HSA) were: Gd.4a (r 1 = 7.6 mM?1s?1 and r 1 = 11.7 mM?1s?1) and Gd.4b. (r 1 = 7.3 mM?1s?1 and r 1 = 16.0 mM?1s?1). These relatively modest increases in r 1 are consistent with the change in inner-sphere hydration on binding to HSA shown by luminescence measurements on Eu.4a/b. Binding constants for HSA determined by the quenching of luminescence (Eu) and enhancement of relaxivity (Gd) were Eu.4a (27,000 M?1 ± 12%), Eu.4b (32,000 M?1 ± 14%), Gd.4a (21,000 M?1 ± 15%) and Gd.4b (26,000 M?1 ± 15%). 相似文献
7.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+ (aq) + SrL2+ (nb) $ \Leftrightarrow $ ML2+ (nb) + Sr2+ (aq) taking place in the two-phase water–nitrobenzene system (M2+ = Ca2+, Pb2+, Cu2+, Zn2+, Cd2+, $ {\text{UO}}_{2}^{2 + } $ , Mn2+, Co2+, Ni2+; L = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the ML2+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order: Cd2+ < Ca2+ < Mn2+ < Cu2+, Zn2+ < $ {\text{UO}}_{2}^{2 + } $ , Co2+ < Ni2+ < Sr2+ < Pb2+. 相似文献
8.
E. Makrlík P. Vaňura Z. Spíchal P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):243-248
Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of 1,3-bis(diphenylphosphino)propane dioxide (DPPPrDO, L) has been investigated. The equilibrium data have been explained assuming that the species $ {\text{HL}}^{ + } ,\,{\text{HL}}_{2}^{ + } ,\,{\text{ML}}^{3 + } \,{\text{and}}\,{\text{ML}}_{3}^{3 + } $ HL + , HL 2 + , ML 3 + and ML 3 3 + (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the complex species in nitrobenzene saturated with water have been determined. It was found that the stability constants of the corresponding complexes $ {\text{EuL}}_{n}^{ 3+ } \,{\text{and}}\,{\text{AmL}}_{n}^{ 3+ } , $ EuL n 3 + and AmL n 3 + , where n = 1, 3 and L is DPPPrDO, in water-saturated nitrobenzene are comparable. 相似文献
9.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(3):593-598
Extraction of microamounts of calcium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of dicyclohexano-18-crown-6 (DCH18C6, L) and dicyclohexano-24-crown-8 (DCH24C8, L) has been investigated. The equilibrium data have been explained assuming that the species HL+, $ {\text{HL}}_{2}^{ + },$ CaL2+ and $ {\text{CaL}}_{2}^{2 + } $ (L = DCH18C6, DCH24C8) are present in the organic phase. The values of extraction and stability constants of the complex species in nitrobenzene saturated with water have been determined. It was found that the stability constants of CaL2+ (L = DCH18C6, DCH24C8) for both ligands under study are practically the same in nitrobenzene saturated with water, whereas in this medium the stability of the complex $ {\text{CaL}}_{2}^{2 + } $ involving the DCH24C8 ligand is somewhat higher than that of $ {\text{CaL}}_{2}^{2 + } $ with the ligand DCH18C6. 相似文献
10.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):633-638
Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of dicyclohexano-18-crown-6 (DCH18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, $ {\text{HL}}_{ 2}^{ + } $ , ML2+ and $ {\text{ML}}_{ 2}^{ 2+ } $ (M2+ = Sr2+, Ba2+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in the mentioned medium the stability constants of the complexes BaL2+ and $ {\text{BaL}}_{2}^{2 + }, $ where L = DCH18C6, are somewhat higher than those of the species SrL2+ and $ {\text{SrL}}_{2}^{2 + } $ with the same ligand L. 相似文献
11.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):615-619
Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B?) in the presence of dicyclohexano-24-crown-8 (DCH24C8, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, $ {\text{HL}}_{2}^{ + }, $ ML2+ and $ {\text{ML}}_{ 2}^{2 + } $ (M2+ = Sr2+, Ba2+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in water–saturated nitrobenzene, the stability constants of the complexes BaL2+ and $ {\text{BaL}}_{ 2}{^{2 + }}, $ where L = DCH24C8, are somewhat higher than those of the corresponding species SrL2+ and $ {\text{SrL}}_{ 2}{^{2 + }} $ with the same ligand L. 相似文献
12.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):947-951
The exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Cs+(nb) ? 1·C+ (nb) + Cs+(aq) occurring in the two-phase water–nitrobenzene system (C+ = protonated α-amino acid methyl ester, 1 = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated on the basis of extraction experiments and γ-activity measurements. Further, the stability constants of the 1·C+ cationic complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: protonated l-tryptophan methyl ester < protonated l-phenylalanine methyl ester < protonated l-leucine methyl ester < protonated l-methionine methyl ester < protonated l-valine methyl ester. 相似文献
13.
Noorjahan Begum Dennis W. Bennett G. M. Golzar Hossain Shariff E. Kabir Ayesha Sharmin Daniel T. Haworth Tasneem A. Siddiquee Edward Rosenberg 《Journal of Cluster Science》2005,16(3):413-428
Treatment of the electronically unsaturated 4-methylquinoline triosmium cluster $[\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu_3\hbox{-}\upeta^{2}\hbox{-}\hbox{C}_{9}\hbox{H}_{5} \hbox{(4-Me)N})(\upmu\hbox{-H})]$ (1) with tetramethylthiourea in refluxing cyclohexane at 81°C gave $[\hbox{Os}_{3}\hbox{(CO)}_{8}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5} \hbox{(4-Me)N})(\upeta^2\hbox{-SC}(\hbox{NMe}_2\hbox{NCH}_2\hbox{Me})(\upmu \hbox{-H})_2]$ (2) and $[\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5}\hbox{(4-Me)N})(\upeta^1\hbox{-SC}(\hbox{NMe}_2)_2)(\upmu\hbox{-H})]$ (3). In contrast, a similar reaction of the corresponding quinoline compound $[\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu_{3}\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N})(\upmu\hbox{-H})]$ (4) with tetramethylthiourea afforded $[\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu\hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N})(\upeta^{1}\hbox{-SC(NMe}_{2})_{2})(\upmu\hbox{-H)}]$ (5) as the only product. Compound 2 contains a cyclometallated tetramethylthiourea ligand which is chelating at the rear osmium atom and a quinolyl ligand coordinated to the Os3 triangle via the nitrogen lone pair and the C(8) atom of the carbocyclic ring. In 3 and 5, the tetramethylthiourea ligand is coordinated at an equatorial site of the osmium atom, which is also bound to the carbon atom of the quinolyl ligand. Compounds 3 and 5 react with PPh3 at room temperature to give the previously reported phosphine substituted products $[\hbox{Os}_{3}\hbox{(CO)}_{9}(\upmu \hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{5}\hbox{(4-Me)N)(PPh}_{3})(\upmu\hbox{-H)}]$ (6) and $[\hbox{Os}_{3}\hbox{(CO}_{9}(\upmu \hbox{-}\upeta^{2}\hbox{-C}_{9}\hbox{H}_{6}\hbox{N)(PPh}_{3})(\upmu\hbox{-H)}]$ (7) by the displacement of the tetramethylthiourea ligand. 相似文献
14.
E. Makrlík P. Selucký P. Vaňura 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):467-470
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + 1·Na+ (org) $ \Leftrightarrow $ 1·M+ (org) + Na+ (aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M+ = Li+, H3O+, NH4 +, Ag+, Tl+, K+, Rb+, Cs+; 1 = benzo-18-crown-6; aq = aqueous phase, org = FS 13 phase) were evaluated. Further, the stability constants of the 1·M+ complexes in FS 13 saturated with water were calculated; they were found to increase in the series of $ {\text{Cs}}^{ + } \, < \,{\text{Rb}}^{ + } \, < \,{\text{H}}_{ 3} {\text{O}}^{ + } \, < \,{\text{Ag}}^{ + } \, < \,{\text{Li}}^{ + } \, < \,{\text{NH}}_{4}^{ + } \, < \,{\text{K}}^{ + } \, < \,{\text{Tl}}^{ + } $ . 相似文献
15.
Behzad Soltani Moayad Hossaini Sadr James T. Engle Christopher J. Ziegler Sang Woo Joo Younes Hanifehpour 《Transition Metal Chemistry》2012,37(8):687-694
Three new binuclear copper complexes of formulae $ \left[ {{\text{Cu}}_{2}^{\text{II}} {\text{Pz}}_{2}^{\text{Me3}} {\text{Br}}_{ 2} \left( {{\text{PPh}}_{ 3} } \right)_{ 2} } \right] $ (1), $ \left[ {{\text{Cu}}_{ 2}^{\text{II}} {\text{Pz}}_{2}^{\text{Ph2Me}} {\text{Cl}}_{ 2} \left( {{\text{PPh}}_{ 3} } \right)_{ 2} } \right] $ (2) and $ \left[ {{\text{Cu}}_{2}^{\text{II}} \left( {{\text{Pz}}^{\text{PhMe}} } \right)_{ 4} {\text{Cl}}_{ 4} } \right] $ (3) (PzMe3?=?3,4,5-trimethylpyrazole, PzPh2Me?=?4-methyl-3,5-diphenylpyrazole and PzPhMe?=?3-methyl-5-phenylpyrazole) have been synthesized and characterized by chemical analysis, FTIR and 31P NMR spectroscopy and single-crystal X-ray diffraction. Complex 1 is a doubly bromo-bridged dimer, while complexes 2 and 3 are chloro-bridged dimers. The Cu(II) centers are in a distorted tetrahedral geometry for 1 and 2 and a distorted square pyramidal N2Cl3 environment for 3. 相似文献
16.
Piotr Szterner 《Journal of Thermal Analysis and Calorimetry》2009,98(1):337-341
The enthalpies of solution $ \Updelta_{sol}^{{}} H_{m}^{{}} $ of polymorphic forms I and II of theophylline in water at 298.15 K using the isoperibol solution calorimeter have been determined in the range of concentration (0.311–1.547) · 10?3 /mol · kg?1. The enthalpies of hydration $ \Updelta_{hyd}^{{}} H_{m}^{o} $ were determined from the experimentally obtained the enthalpies of solution for aqueous solutions and previously determined enthalpies of sublimation $ \Updelta_{s}^{g} H_{m}^{o} . $ 相似文献
17.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):393-398
Solvent extraction of microamounts of trivalent europium and americium into nitrobenzene by using a synergistic mixture of hydrogen dicarbollylcobaltate (H+B?) and magnesium ionophore III (L) was studied. The equilibrium data were explained assuming that the species HL+, \( \text{HL}_{2}^{ + } , \) \( {\text{ML}}_{2}^{3 + } , \) and \( {\text{ML}}_{3}^{3 + } \) (M3+ = Eu3+, Am3+; L = magnesium ionophore III) are extracted into the nitrobenzene phase. The values of extraction and stability constants of the cationic complex species in nitrobenzene saturated with water were determined and discussed. 相似文献
18.
Stephanie Spahr Sebastian Huntscha Jakov Bolotin Michael P. Maier Martin Elsner Juliane Hollender Thomas B. Hofstetter 《Analytical and bioanalytical chemistry》2013,405(9):2843-2856
Compound-specific isotope analysis (CSIA) is an important tool for the identification of contaminant sources and transformation pathways, but it is rarely applied to emerging aquatic micropollutants owing to a series of instrumental challenges. Using four different benzotriazole corrosion inhibitors and its derivatives as examples, we obtained evidence that formation of organometallic complexes of benzotriazoles with parts of the instrumentation impedes isotope analysis. Therefore, we propose two strategies for accurate $\delta^{13}$ C and $\delta^{15}$ N measurements of polar organic micropollutants by gas chromatography isotope ratio mass spectrometry (GC/IRMS). Our first approach avoids metallic components and uses a Ni/Pt reactor for benzotriazole combustion while the second is based on the coupling of online methylation to the established GC/IRMS setup. Method detection limits for on-column injection of benzotriazole, as well as its 1-CH $_{3}$ -, 4-CH $_{3}$ -, and 5-CH $_{3}$ -substituted species were 0.1–0.3 mM and 0.1–1.0 mM for δ13C and δ15N analysis respectively, corresponding to injected masses of 0.7–1.8 nmol C and 0.4–3.0 nmol N, respectively. The Ni/Pt reactor showed good precision and was very long-lived ( $>$ 1000 successful measurements). Coupling isotopic analysis to offline solid-phase extraction enabled benzotriazole-CSIA in tap water, wastewater treatment effluent, activated sludge, and in commercial dishwashing products. A comparison of $\delta ^{13}$ C and $\delta ^{15}$ N values from different benzotriazoles and benzotriazole derivatives, both from commercial standards and in dishwashing detergents, reveals the potential application of the proposed method for source apportionment. 相似文献
19.
E. Makrlík P. Selucký P. Vaňura 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):767-770
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Na+(nb) ? 1·C+(nb) + Na+(aq) taking place in the two-phase water–nitrobenzene system (C+ = univalent organic cation, 1 = benzo-18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1·C+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: protonated tyramine, protonated l-valine methyl ester < protonated dopamine < protonated serotonin < methylammonium < protonated hexamethylenetetramine < ethanolammonium < protonated dl-noradrenaline. 相似文献
20.
Yohei Takahashi Masatoshi Endo Kazuaki Ito 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(1-2):237-245
The synthesis, characterization and binding studies with anions for biaryl-based anion receptors bearing thiourea groups have been described. The results revealed that receptors (1 and 2) showed good selectivity and binding affinity for F?, and among them binaphthyl-based receptor (1a) showed the best binding affinity for F? in comparison to other tested anions (Cl?, Br?, I?, $ {\text{NO}}_{3}^{ - } ,\;{\text{HSO}}_{4}^{ - } , $ AcO? and $ {\text{H}}_{2} {\text{PO}}_{4}^{ - } $ ). This is probably due to the fact that the moderate rigidity of binaphthyl skeleton in 1a is able to provide the better geometry of two thiourea groups for incorporating F? into the binding pocket. The higher basicity of F? also participated in this selectivity. 相似文献